The present invention relates to a clock and more particularly pertains to a clock with intelligent backlight device.
The available clocks in the marketplace can generally be divided into analogue type and digital type. Some clocks are equipped with luminous devices to enable users to view the time in the dark. In regard to analogue clocks, some clock surfaces and clock hands are made of luminous material, and so can emit self-generated light in the dark without any electric power. However, since luminous material can only be luminous after absorbing light, it cannot emit light continuously for long. Further, the quality of luminous material varies a lot and the illuminating effect is generally not very good. Surfaces of some analogue clocks are installed with small light bulbs or light emitting diodes. When a user presses a button, the light will be turned on illuminating the clock surface, but it is very difficult and inconvenient to look for the clock and press the button in the dark. With respect to digital clocks, some clocks use light emitting diodes to display the time, but these clocks require alternate currents and they are inconvenient for the users as the locations of the electric cables and sockets may cause problems. Most of the digital clocks in the marketplace display time by way of liquid crystal displays (LCDs), but LCDs themselves are not luminous. In the daytime the time and images can be displayed by reflection of sunlight, but in a dark environment a backlight source must be provided so as to display the images. If the backlight source emits uneven light, the sharpness of the display will be affected.
In addition, clocks that are powered by dry batteries generally do not address the problem of power supply management and are not installed with components that control the voltage or current. For example, when new batteries are used, the LCD device and its backlight device consume higher voltage and current, and so the backlight is brighter. But not for long the backlight of the LCD device will become dim, following the consumption of the electric power of the batteries. This forces the user to replace the batteries before they are used up, which not only causes wastage, but also affects the visual appearance due to inconsistent brightness of the backlight.
Besides, though the above-mentioned clocks can display the time in the dark, they also emit light in the daytime and this wastes electric power. For that reason, there is a market demand for clocks that can automatically switch on the backlight devices in response to changes in the luminosity of the surroundings and can simultaneously provide effective power supply management.